metamorphic
Quartzite
Quartzite (SiO2)
Hardness: 7 on Mohs scale. Color: Off-white to light tan/brownish with sugary texture. Luster: Vitreous to dull. Crystal structure: Trigonal (interlocking quartz grains). Cleavage: None (conchoidal to uneven fracture).
- Hardness
- 7 on Mohs scale
- Color
- Off-white to light tan/brownish with sugary texture
- Luster
- Vitreous to dull
Identified More metamorphic →
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Physical properties
Hardness: 7 on Mohs scale. Color: Off-white to light tan/brownish with sugary texture. Luster: Vitreous to dull. Crystal structure: Trigonal (interlocking quartz grains). Cleavage: None (conchoidal to uneven fracture).
Formation & geological history
Formed through the regional metamorphism of quartz-rich sandstone under extreme heat and pressure, causing quartz grains to recrystallize and fuse tightly together.
Uses & applications
Used in construction as crushed stone for railway ballast, road base, and dimension stone for countertops and building facades.
Geological facts
Quartzite is so tough and resistant to weathering that it often forms prominent ridges and hilltops in eroded mountain belts. It is significantly harder and more durable than marble or sandstone.
Field identification & locations
Identified by its sugary granular texture that breaks through quartz grains rather than around them, and its ability to easily scratch glass. Commonly found in mountainous metamorphic terrains worldwide.
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